Contour bowling pin



March 22, 1966 F. E. sATcHL-:LL ETAL 3,241,835

CONTOUR BOWLING PIN Filed June 28, 1963 I5 Sheets-Sheet l Mal'Ch 22, 1966 F. E. sATcHELI. ETAL 3,241,835

CONTOUR BOWLING PIN 5 Sheets-Sheet 2 Filed June 28, 1963 March 22, 1966 F. E. sATcHELL ETAL 3,241,835

CONTOUR BOWLING PIN United States Patent C 3,241,835' CONTOUR BOWLING PIN Fred E. Satchell, Grand Haven, Mich., William L. lolita, (laks, la., and .lohn J. Weisz, Muskegon, and Anton W. Rytina, Grand Haven, Mich., assignors to Brunswick Corporation, a corporation of Delaware Filed June 28, 1963, Ser. No. 291,372 8 Claims. (Cl. 273-82) This invention relates to lbowling pins and more particularly to bowling pins having hard contoured cores. This invention further relates t` adjustments or control of scoring properties of bowling pins having hard core surfaces.

Conventionally, regulation bowling pins are constructed essentially of a hard core usually having a plastic coating over the core. The American Bowling Congress, the major regulatory body with respect to bowling pin specifications, has prescribed that regulation ten pins shall be of sound, hard maple. Further, a weight range for regulation pins and a maximum variance in weight between pins of a set is also prescribed. With dwindling supplies of suitable maple stock and resulting increased cost of such stocks, it would be highly desirable to be able to substitute other hard materials for the maple core. Among such other materials are other woods, hard plastics, metals and the like. Many attempts to find such materials suitable for suchuse have been unsuccessful, resulting in pins having playing characteristics, and particularly scoring characteristics, suiciently different from those of the hard maple core pin to render the new or synthetic pins unacceptable, for substitution for maple core pins. It is therefore desirable -to correct the scoring characteristics o-f such synthetic pins to correspond more closely with scoring characteristics of a regulation maple pm.

It is a general object o-f this invention to provide for adjustment or alt-eration of scoring characteristics of hard core bowling pins. Another object of this invention is to provide for adjustment or alteration of flight pattern characteristics of hard core bowling pins.

It is still another object of this invention to provide a bowling pin having a hard core and a resilient cover or coating wherein the core includes a portion disposed adjacent the plane of normal ball impact, which portion of the core is adapted to receive a sufficient -amount o-f ball impact forces to control the action of the pin.

A further object is to provide a bowling pin having a hard core in accordance with the foregoing objects wherein the coating material is more elastic than the core and is capable of temporarily deforming under normal impact of a bowling ball sufficient to transfer impact forces to the core and especially to that portion of the core disposed adjacent the plane of normal ball impact.

A still further object is to provide such a bowling pin wherein the elastic coating includes an inner coating and an outer coating and especially where the inner coating is a resilient elastomeric polyurethane resin and the outer coating is polyurethane lacquer.

Yet another object of this invention is to provide a bowling pin in accordance with the foregoing objects wherein the hard core is a hollow metal core.

An additional object of this invention is to provide a method for making bowling pins of the foregoing objects.

Further objects will beco-me readily apparent from the following detailed description taken in connection with the .accompanying drawings, in which:

FIGURE 1 is a vertical section through an embodiment of the bowling pin of this invent-ion;

FIGURE 2 is a vertical section through another embodiment of the bowling pin of this invention;

3,2%,335 Patented Mar. 22, 1966 f. ICC

FIGURE 3 is a chart of the ight pattern of a metal core bowling pin for comparison purposes;

FIGURE 4 is a chart of the flight pattern of an embodiment of this invention similar to that illustrated in FIGURE 1; and

FIGURE 5 is a chart of the flight pattern of an embodiment of the bowling pin of this invention similar to that illustrated in FIGURE 2.

While illustrative embodiments o-f the invention are shown in the drawings and will be described in detail herein, the invention is susceptible of embodiment in many different form-s, and it should be understood that the present disclosure is to be considered Ias an exemplication of the principles of the invention and is not intended to limit the scope to the embodiments illustrated.

It is contemplated that the bowling pins of the present invention are to be used in bowling games, such as ten pins, and are to be struck by a ball in the manner normally occurring during such bowling games. Therefore, in the embodiments of bowling pins illustrated in FIG- URES 1 and 2, bowling balls l2 and 22 respectively, have been shown in general outline at the position of impact with the standing bowling pins. In view of the general symmetry o-f the bowling pin, it is readily seen that the various points of impact of the ball against the pin, differing merely circumferentially depending upon the orientation of the pin, will fall upon an imaginary plane. In the bowling pin of conventional core construction, where the outer surface of the core generally follows the approximate configuration of the outer surface of the pin coating, this imaginary plane will coincide with or will be parallel and proximate to the plane of major force transfer to the solid core, i.e., the imaginary plane defined by the points of greatest force exerted upon the core by impact of a bowling ball with the pin regardless of orientation of the pin. Generally, in accordance with the present invention, the impact forces against a hard pin core are directed above or below their nor-mal direction sufliciently to change the translational motion of the pin when struck, e.g., by change in moment of the pin and/ or by vectoring forces.

Referring now more particularly to the drawings, there is illustrated in FIGURE 1 an embodiment of this invention wherein a high indented contour non-symmetrical in vertical section, is provided on the pin core with a projection below the normal point of impact of a bowling ball. In FGURE l the bowling pin is indicated generally by reference numeral 11. Pin 11 includes a hollow metal, e.g., metal or metal alloy such as magnesium or aluminum or the like, core 13. Core means are provided for controlling the core contour and the action or flight of the pin as shown by an indentation in the belly portion circumferentially disposed about the pin and defined by surfaces 13a and 13d formed integrally with the core. However, the core means can be included in other ways such as by slipping a projecting ring of material over an undersized core.

The indentation provides an annular ridge integral with the core and disposed about the pin below the plane of normal impact points, which annular ridge is indicated at 13b. Above annular ridge 13b surface 13a progresses inwardly at an angle of 30 from the vertical. The plane of normal impact points bisects this 30 angular surface 13a (which consists of a conical section). Surface 13d extends from surface l3nt generally upwardly in cylindrical disposition to the surface of the normal core configuration at 13a, where a second circular ridge is formed by the juncture of the indentation with the normal core contour. It will be noted that ridge 13b is closer to the plane of normal impact points than is ridge 13C.

It is to be understood that the included angle of the annular ridge can be any angle up' to 90 or higher. Further, the angular surface can be omitted, in which case the annular ridge alone can function as the core means for receiving a sufficient amount of ball impact forces for controlling the pin action. It should also be understood that the angular surface, e.g. 13a, can be greater or less than 30; the annular ridge can be omitted or removed sufficiently from the ball impact area so that the angular surface alone may function as the core means for receiving a sufficient amount of ball impact forces for controlling the pin action.

Pin 11 is provided with a cover or coating 14 which is sufficient, in combination with base member 15, to bring the core up to regulation pin size. Coating 14 includes an inner coating 14C and an outer coating 14b. The portion of the inner coating indicated at 14a is sufiiciently thick to fill in the indentation to provide a smooth, normal appearing pin outer surface in the region of the indentation.

The outer coating 14b is a polyurethane lacquer although other pin coating compositions, such as nitrocellulose or ethylcellulose lacquers, cellulose acetate, cellulose acetate and butyrate, and the like may be used. The inner coating at 14C is a resilient elastromeric composition, e.g. resilient polyurethane resin, natural rubber, butyl rubber, etc. As a more specific example, coating 14e can be a resilient polyurethane resin having a hardness of about Shore-A 46 and formed from a mixture of 100 parts by weight Adiprene D-lOO (a condensation product of toluene diisocynate and 1,4-butanediol), 9 parts by weight castor oil and 3.2 parts by weight 1,4-butanediol by curing the mixture for about three hours at about 285 F.

In making the bowling pin, the inner coating material is applied to core 13 and cured. The bowling pin core and coating is then turned to a size slightly smaller than the regulation bowling pin size and the outer coating 14b is applied to bring the pin up to regulation size, with subsequent finishing as needed or desired.

Referring now more particularly to FIGURE 2, there is illustrated another embodiment of the bowling pin of the present invention. Pin 21 is illustrated in association with ball 22 aligned with the normal plane of impact points. Pin 21 includes hollow metal core 23 and coating 24 including the thicker portion of the coating indicated at 24a adjacent surfaces 23a and 23d. Coating 24 is made up of an inner coating 24:,` and an outer coating 24b of the same composition as coatings 14C and 14b respectively of the embodiment of FIGURE l. The pin base member is indicated by reference numeral 25. It will be seen that the embodiment of FIGURE 2 is the same as that of FIGURE 1 except for the positioning of the indentation and the corresponding thicker portion of coating material. Again the contouring of the core surface is unsymmetrical with respect to the plane of impact points on the pin surface. Thus, in the embodiment of FIGURE 2, the indentation begins at ridge 23b, follows surface 23a conically inward and downward crossing the plane of impact points. Surface 23d extends downward from surface 23a to ridge 23C on the surface of core 23 and is disposed to receive an appreciable portion of impact forces from a bowling ball bowled against the pin in a normal manner. Annular ridge 23b is disposed above the plane of normal impact and is also disposed to receive an appreciable portion of the impact forces.

In the embodiments of FIGURES 1 and 2 respectively, surfaces 13a and 23a apparently function as force receiving surfaces and cause vectoring of the force downward and upward respectively. Additionally, ridges 13b and 23b apparently function as force receiving ridges which, being disposed from the plane of impact points respectively lower or raise the major moment forces in the pin under impact conditions. The contour of the pin core in either embodiment illustrated can be considered as including either an indentation as defined by surfaces 13a and 13d or 23a and 23d or as including a projection as defined by annular ridges 13b and 23b. The core and indentation or projection can be shaped by molding, grinding, turning combinations thereof, etc., or a projection may be added to a formed partially undersized ol partially shaped core.

Although the coating materials of the illustrated embodiments have been specifically identified, it is to be understood that any coating materials have sufiiicent elasticity to be deformable under impact of a bowling ball are usable. The coating material should be suficently resilient to maintain the outer shape of the bowling pin after repeated impacts. The coating is softer and more elastic than the hard core to permit transmission of 1m pact forces through the coating to the core. Preferably the coating is resistant to cold iiow. We have found coat ing materials having a modulus of elasticity in compression within the range of 10,000 to 13,000 p.s.i. (Baldwin- Lima-Southwork 60-ton compression with a loading rate of 2,000 p.s.i.min.) to be entirely satisfactory. Any materials with lower moduli of elasticity will of course be suitable since such materials would permit effective transfer of force to the core. Although no upper limit has been found, materials with even much higher moduli of elasticity will be usable. However, the modulus of elas ticity would have to be substantially lower than that of the hard core material. Materials having a Shore-A hardness up to 62 or higher may be usable. We have successfully used materials having Shore-A hardness of 40 to 41 and any softer materials would be usable so long as the property of resiliency is retained.

As to the structure of the coating, it is considered more advantageous to provide an inner and outer coating as was provided in the illustrated embodiments. The outer surface of the coated pin, e.g. the outer coating or an outer layer of coating, prevents discoloring of the pin, e.g. by dirt, and reduces the coefficient of friction of the outer pin surface.

In selecting a coating for use in accordance with the present invention, it may be desirable to consider the sound chara-cteristics of the coating material as a portion of the pin structure. Further, in addition to greater elasticity than that of the hard core, it will be often desirable to select a coating having a coefficient of restitution suffiicent to provide a velocity to the pin greater than the velocity of the ball after impact of the pin with the ball. Also, the thickness in which the coating is to be applied and the nature of the core material may affect the selection of a suitable coating material with respect to sound characteristics, elasticity of the coating and coefficient of restitution.

Referring now to FIGURES 3 through 5 of the drawings, there are illustrated flight patterns of various bowling pins. Each pattern was obtained by using a pendulum impactor to strike a pin on its normal impact plane. The pendulum impactor consists of a bowling ball suspended at one end of a long rod, the other end of which rotates around a shaft like a pendulum. The ball is lifted to the same height for each impact and, when released, swings through the same arc. During the test, each of the pins was positioned two feet eight inches from the end of the pin deck. The ball was permitted to strike the pin toward the end of the pin deck and the moving pin was photographed in various positions of flight. The fiight pattern representations illustrated in FIGURES 3 through 5 were made from the photographs of actual flight patterns.

The fiight pattern illustrated in FIGURE 3 was obtained using a hollow metal core pin having a normal core contour, an epoxy modified polyurethane coating over the core and a nitrocellulose surface coating. The flight pattern was photographed at approximately 1350 frames per second.

FIGURE 4 shows a flight pattern of a bowling pin of similar construction to that of the bowling pin of FIG` URE 1; the flight pattern was photographed at approximately 1150 frames per second.

The flight pattern of FIGURE 5 is that of a bowling pin similar to the embodiment illustrated in FIGURE 2 photographed at approximately 1400 frames per second. The legend given in the drawings, identifying the position of the top, bottom, center of gravity of the pin and center of the ball, applies to all of FIGURES 3 through 5. In the figures, the numbers adjacent the indication of the center of the ball identify the number of the frame in which the ball was photographed in the indicated position. The frame numbers are also given for the pin at the identied top and bottom positions.

Cores of all pins tested were machined to size and thereafter coated to form the test pins. The slop of the conical surface, i.e., corresponding to surfaces 13a and 23a in FIGURES l and 2, on the contoured pins (ilight patterns illustrated in FIGURES 4 and 5) was 30 from vertical and the sloped surface extended from .300 inch on one side of the plane of exterior pin impact points to .300 inch on the other side, depending on the direction of the contouring.

Referring to FIGURE 3, it is seen that after impact of the uncontoured metal core pin with the ball, the pin center of gravity rises 81/2 inches above the pin deck while the pin rotates about its horizontal axis. Since the pin head contacts the pin deck at 2 feet 11/2 inches (about frame 115), 180 rotation of the pin is not completed. The pin head bounces off the pin deck and the center of gravity rise, therefore, is not linear. The flight pattern picture is typical for this type of pin with an uncontoured core. The flight pattern is included to compare with the flight patterns of FIGURES 4 and 5 so that the changes in flight pattern produced by contouring the pin core are more apparent.

Turning to FIGURE 4, there is shown a flight pattern of a metal core pin with the core contoured or indented above the ball impact point as :shown in FIGURE 1. The flight pattern is characterized by a rise in center of gravity to '1/2 inches in 140 frames. The pin r-otates only 90 around its horizontal axis `in the four feet of trajectory studied. The pin base is beyond four feet from the impact position at approximately the same time as the control pinin FIGURE 3. The pin head does not strike the pin deck, but does come in contact with the ball between 0.035 and 0.054 second (between frames 40 and 60) after initial impact. This second impact with the ball stops horizontal rotation and drives the pin straight out away from the ball. Thus, the pin, because of its core contour, undergoes a combination of increased speed of rotation and lowered trajectory after impact which permits an additional impact of the head of the pin with the ball. This results in the net effect of driving the pin away from the ball horizontal to the pin deck.

FIGURE 5 shows the ilight pattern of a metal core pin with the core contoured below the ball impact point providing an annular tracjection above the impact point. The center of gravity of this pin, with reference to the flight pattern, rises more rapidly than the control, being at 7 inches from the deck at 0.014 second (frame 20) cocmpared to the control pin where the llight `is only 6.4 inches from the deck in 0.015 second (frame 20). The center of gravity rises higher, i.e., to 10.8 inches a-t four feet (between frames 190 and 195) than the control pin or the pin having the flight pattern of FIGURE 4. This higher rise prevents the head from striking the deck and permits a full 180 rotation around the horizontal axis. The pins travel slower with respect to Iground speed than either of the other pins. Thus, again the trajectory of the pin has been materially altered by contouring of the core.

It is reasonable, in view of the fact that when pins are struck by a bowling ball they are known to knock down other pins by their action, the major factors in- 6, fluencing lscoring characteristics of pins are the pin trajectory, amount of rotation in any plane and the speeds of trajectory and rotation. The contours, to be effective in altering or controlling these factors, must be on the outside of the hard pin core and should be unsymmetrical with respect to the continuous line of impact points around the pin. The irregularities of the core are filled by the resilient elastomeric coating, producing a smooth, normally appearing pin on the surface. The elastomeric coating is indentable and permits transfer of the force from the ball to the pin core. As the force hits the pin core, it may be considered as a vector force angled upwardly or downwardly in accordance with the contouring of the pin e.g. where angular core surfaces are used, or it may be considered as creating a different rotational moment in a pin by such vector force and/ or by being transferred to the core as a resul-t of vectoring, at a lower or higher position or angle than normal, i.e., more dist-ant or closer, with respect to the center of gravity of the pin. Alternatively, the contouring may be considered merely as creating the different rotational moment in the pin by transfer of appreciable force to the core at a higher or lower position, e.g. where annular ridges are used in the absence of an angular vectoring surface so that appreciable force is transferred to the core at the ridge. The speed of the pin is also somewhat controlled by the contouring.

In order to show that the change in core contouring of the pin affects scorin-g characteristics of the pin, scoring tests were conducted on sets of pins identical to those tested with respect to trajectory as reported with reference to FIGURES 4 and 5. For control purposes, a plastic coated wood pin, acceptable by American Bowling Congress standards, was also tested. Further, a pin having a metal core contoured to provide the effective force of impact at or very close to the plane of impact was tested for comparison purposes.

The test procedure was a cyclic procedure wherein each cycle consisted of bowling a ball toward a `set of triangularly disposed bowling pins on a bowling alley. An automatic pinsetter was employed and the ball was bowled and directed for accuracy. Return of the ball from the pit by the automatic pinsetter completed each cycle. In the test, each set of pins was tested by bowling the ball to each of the same variety of preselected positions ranging from dead center of the #1 pin outwardly. A predetermined number of cycles were completed for each pin structure and for each of the bowling positions.

The identity of positions of pins standing after each cycle was noted and reference was then made to a score table of average net score increments to a bowler who bowls at a preselected average, to translate the pin positions into a bowling score. The test procedure was been found to correlate closely with actual bowlers scores in testing various pins.

The following pins were tested in accordance with the above procedure with results recorded below in terms of test bowling score as derived and computed from the score table:

Test bowling Pin tested: score Plastic coated wood pin 173.7 Plastic coated metal pin for comparison 183.7 Plastic coated metal core pin with high contour, tested for trajectory with reference to FIGURE 4 Plastic coated metal core pin with low contour, tested for trajectory with reference to FIGURE 5 176.4

The above test results show that the pins prepared in accordance herewith were closer in scoring characteristics to the plastic coated wood pin than was the pin prepared for comparison purposes. As was indicated above, it is not always desirable to increase the scoring characteristics of pins. As shown from the above data, some pins score too highly when compared with wood pins 7 and are therefore not desirable. Thus, the target for changing scoring characteristics of pins is the score of a wood pin and the above data demonstrates that the contouring of a metal core can be used to change the scoring characteristics of a pin to make the pin score more closely to a wood pin. In fact, the :pin with the contour scored well within five pins of the wood pin, a deviation sometimes occurring between pins in a regulation set.

Analysis of the individual cycles of the above test showed that both the high and low contouring of the metal cores strengthened the thin hit area in bowling, a desirable characteristic of pins. It was found that providing a projection impact surface below the normal irnpact point improves a pin with high translation action while providing a higher projection improves a pin with low translation action.

It is evident that we have provided a control of the travel patterns and scoring characteristics of a hard core bowling pin, especially a metal core pin. Of course, the present invention may also be used to change the scoring and flight pattern characteristics of wood core pins, for example pins made of heavier than norma-l wood. Additionally, vertical ribbing or contouring and/or diagonal ribbing or contouring can be used to affect the travel of the pin.

It is believed that the ability to control pin action by varying the core contour will prove to be a valuable tool for obtaining satisfactory score characteristics in many cases where such satisfactory characteristics have not heretofore been obtained. The contouring may be used to create predetermined flight patterns, if desired, by correlating the contouring or configuration of the pin with particular flight patterns or even with particular scoring characteristics in a given pin. Thus, the present invention provides a technique for altering pin structure to bring score of a given pin structure into an acceptable range either by raising the score or lowering the score obtained with the pin. It has been shown herein above that the present invention is capable of accomplishing this adjustment of scoring characteristics.

We claim:

1. A bowling pin having a hard core and a coating thereover of material more elastic than said core and capable of temporarily deforming under normal impact of a bowling ball suflicient to transfer impact forces to said core, said core being of a configuration providing an indentation in the outer surface thereof in the belly portion peripherally extending about the pin, said indentation having the plane of its beginning adjacent and parallel to the normal plane of ball impact of said core, said indentation traversing said plane and extending beyond said plane to the core exterior a greater distance than the distance from said plane to the beginning of said indentation.

2. The bowling pin of claim 1 wherein said elastic coating material comprises a polyurethane resin.

3. The bowling pin of claim 1 wherein said elastic coating material comprises a linear copolymer of 1,4- butanediol and toluene diiscocyanate harden by treatment with methylene bischloraniline.

4. The bowling pin of claim 1 wherein said elastic coating comprises an inner coating and an outer coating, said outer coating being of generally uniform thickness.

5. The bowling pin of claim 4 wherein said inner coating is a resilient elastomeric polyurethane resin and said outer coating is polyurethane lacquer.

6. The bowling pin of claim 1 wherein said hard core is a one-piece core.

7. The bowling pin of claim 1 wherein one wall of said indentation comprises a cylindrical surface on the core, and a rib extending outwardly from said surface and defining said beginning of the indentation and another wall of said indentation.

8. The bowling pin of claim 7 wherein the rib has one surface defining said beginning and other wall of s a i d indentation and another surface having the general shape of a bowling pin in the belly region and continuing to substantially the lower end of the core.

References Cited by the Examiner UNITED STATES PATENTS 1,583,824 5/1926 Bishop 273--82 2,517,116 8/1950 Klinger 273-82 2,978,375 4/1961 Grawey 273-82 X 3,044,777 6/ 1962 Friedman 273-82 3,141,672 7/ 1964 Unterbrink 273-82 DELBERT B. LOWE, Primary Examiner. 

1. A BOWLING PIN HAVING A HARD CORE AND A COATING THEREOVER OF MATERIAL MORE ELASTIC THAN SAID CORE AND CAPABLE OF TEMPORARILY DEFORMING UNDER NORMAL IMPACT OF A BOWLING BALL SUFFICIENT TO TRANSFER IMPACT FORCES TO SAID CORE, SAID CORE BEING OF A CONFIGURATION PROVIDING AN INDENTATION IN THE OUTER SURFACE THEREOF IN THE BELLY PORTION PERIPHERALLY EXTENDING ABOUT THE PIN, SAID INDENTATION HAVING THE PLANE OF ITS BEGINING ADJACENT AND PARALLEL TO THE NORMAL PLANE OF BALL IMPACT OF SAID CORE, SAID INDENTATION TRASVERING SAID PLANE AND EXTENDING BEYOND SAID PLANE TO THE CORE EXTERIOR A GREATER DISTANCE THAN THE DISTANCE FROM SAID PLANE TO THE BEGINNING OF SAID INDENTATION. 